[Android] Fix Border clipping issues

src/Controls/samples/Controls.Sample.UITests/Issues/BorderWithDifferentShapes.xaml

@@ -0,0 +1,175 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.BorderWithDifferentShapes"
+             Title="Border Shape Test">
+    <ContentPage.Resources>
+        <ResourceDictionary>
+
+            <Style TargetType="Label">
+                <Setter Property="FontSize" Value="10" />
+            </Style>
+
+            <Style TargetType="Border">
+                <Setter Property="Stroke" Value="Red" />
+                <Setter Property="HeightRequest" Value="80" />
+                <Setter Property="WidthRequest" Value="80" />
+            </Style>
+
+            <Style TargetType="Image">
+                <Setter Property="Aspect" Value="AspectFill" />
+            </Style>
+
+        </ResourceDictionary>
+    </ContentPage.Resources>
+    <Grid
+        Padding="12"
+        ColumnDefinitions="*, *, *"
+        RowDefinitions="Auto, Auto, Auto, *">
+        <!-- NO STROKE -->
+        <StackLayout>
+            <Label 
+                AutomationId="WaitForStubControl"
+                Text="Rectangle without Stroke"/>
+            <Border
+                StrokeShape="Rectangle"
+                StrokeThickness="0">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="1">
+            <Label 
+                Text="RoundRectangle without Stroke"/>
+            <Border  
+                StrokeShape="RoundRectangle 12, 0, 0, 12"
+                StrokeThickness="0">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="2">
+            <Label 
+                Text="Ellipse without Stroke"/>
+            <Border
+                StrokeShape="Ellipse"
+                StrokeThickness="0">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <!-- SMALL STROKE -->
+        <StackLayout
+            Grid.Row="1">
+            <Label 
+                Text="Rectangle with Stroke"/>
+            <Border
+                StrokeShape="Rectangle"
+                StrokeThickness="1">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="1"
+            Grid.Row="1">
+            <Label 
+                Text="RoundRectangle with Stroke"/>
+            <Border  
+                StrokeShape="RoundRectangle 12, 0, 0, 12"
+                StrokeThickness="1">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="2"
+            Grid.Row="1">
+            <Label 
+                Text="Ellipse with Stroke"/>
+            <Border
+                StrokeShape="Ellipse"
+                StrokeThickness="1">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <!-- BIG STROKE -->
+        <StackLayout
+            Grid.Row="2">
+            <Label 
+                Text="Rectangle with Stroke"/>
+            <Border
+                StrokeShape="Rectangle"
+                StrokeThickness="10">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="1"
+            Grid.Row="2">
+            <Label 
+                Text="RoundRectangle with Stroke"/>
+            <Border  
+                StrokeShape="RoundRectangle 12, 0, 0, 12"
+                StrokeThickness="10">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="2"
+            Grid.Row="2">
+            <Label 
+                Text="Ellipse with Stroke"/>
+            <Border
+                StrokeShape="Ellipse"
+                StrokeThickness="10">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <!-- STROKEDASHARRAY -->
+        <StackLayout
+            Grid.Row="3">
+            <Label 
+                Text="Rectangle with StrokeDashArray"/>
+            <Border
+                StrokeShape="Rectangle"
+                StrokeThickness="4"
+                StrokeDashArray="1, 1">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="1"
+            Grid.Row="3">
+            <Label 
+                Text="RoundRectangle with StrokeDashArray"/>
+            <Border  
+                StrokeShape="RoundRectangle 12, 0, 0, 12"
+                StrokeThickness="4" 
+                StrokeDashArray="1, 1">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+        <StackLayout
+            Grid.Column="2"
+            Grid.Row="3">
+            <Label 
+                Text="Ellipse with StrokeDashArray"/>
+            <Border
+                StrokeShape="Ellipse"
+                StrokeThickness="4" 
+                StrokeDashArray="1, 1">
+                <Image 
+                    Source="oasis.jpg"/>
+            </Border>
+        </StackLayout>
+    </Grid>
+</ContentPage>

src/Controls/samples/Controls.Sample.UITests/Issues/BorderWithDifferentShapes.xaml.cs

@@ -0,0 +1,17 @@
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+using Microsoft.Maui.Platform;
+
+namespace Maui.Controls.Sample.Issues
+{
+	[XamlCompilation(XamlCompilationOptions.Compile)]
+	[Issue(IssueTracker.None, 018071, "Validate Border using different shapes",
+		PlatformAffected.Android | PlatformAffected.iOS | PlatformAffected.UWP)]
+	public partial class BorderWithDifferentShapes : ContentPage
+	{
+		public BorderWithDifferentShapes()
+		{
+			InitializeComponent();
+		}
+	}
+}

src/Controls/samples/Controls.Sample.UITests/Issues/Issue18071.cs

@@ -0,0 +1,56 @@
+using Microsoft.Maui;
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Graphics;
+using Microsoft.Maui.Controls.Shapes;
+
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 18071, "Windows and Android no longer draw Borders/clipping correctly", PlatformAffected.Android | PlatformAffected.UWP)]
+	public class Issue18071 : TestContentPage
+	{
+		protected override void Init()
+		{
+			Title = "Issue 18071";
+			BackgroundColor = Colors.CornflowerBlue;
+
+			VerticalStackLayout verticalLayout = new VerticalStackLayout();
+			Content = verticalLayout;
+
+			var infoLabel = new Label
+			{
+				AutomationId = "WaitForStubControl",
+				Text = "Without weird clipping image, the test has passed."
+			};
+			verticalLayout.Add(infoLabel);
+
+			Border border = new Border
+			{
+				Background = Colors.Yellow,
+				Stroke = Colors.Red,
+				StrokeThickness = 10
+			};
+			verticalLayout.Add(border);
+
+			AbsoluteLayout abs = new AbsoluteLayout();
+			border.Content = abs;
+
+			Image image = new Image
+			{
+				Source = "oasis.jpg",
+				Aspect = Aspect.AspectFill
+			};
+			abs.Add(image);
+
+			SizeChanged += delegate
+			{ 
+				if (Width > 0)
+				{
+					int width = (int)Width;
+					border.WidthRequest = border.HeightRequest = width * 0.5;
+					image.WidthRequest = image.HeightRequest = width * 0.5;
+					border.StrokeShape = new RoundRectangle() { CornerRadius = width * 0.25 };
+				}
+			};
+		}
+	}
+}

src/Controls/tests/UITests/Tests/Issues/BorderWithDifferentShapes.cs

@@ -0,0 +1,22 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.AppiumTests.Issues
+{
+	class BorderWithDifferentShapes : _IssuesUITest
+	{
+		public BorderWithDifferentShapes(TestDevice device)
+			: base(device)
+		{ }
+
+		public override string Issue => "Validate Border using different shapes";
+
+		[Test]
+		public void BorderWithDifferentShapesTest()
+		{
+			App.WaitForElement("WaitForStubControl");
+			VerifyScreenshot();
+		}
+	}
+}

src/Controls/tests/UITests/Tests/Issues/Issue18071.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.AppiumTests.Issues
+{
+	public class Issue18071 : _IssuesUITest
+	{
+		public Issue18071(TestDevice device) : base(device) { }
+
+		public override string Issue => "Windows and Android no longer draw Borders/clipping correctly";
+
+		[Test]
+		public void Issue18071Test()
+		{
+			this.IgnoreIfPlatforms(new TestDevice[] { TestDevice.iOS },
+				"Currently fails on Android and Windows; see https://github.com/dotnet/maui/issues/17125");
+
+			App.WaitForElement("WaitForStubControl");
+			VerifyScreenshot();
+		}
+	}
+}

src/Core/src/Platform/Android/ContentViewGroup.cs

@@ -115,13 +115,14 @@ internal IBorderStroke? Clip
 			if (Clip is null || Clip?.Shape is null)
 				return null;
 
+			IShape clipShape = Clip.Shape;
+			bool isRoundRectangle = clipShape is IRoundRectangle;
 			float density = _context.GetDisplayDensity();
 			float strokeThickness = (float)Clip.StrokeThickness;
-			float w = (width / density) - strokeThickness;
-			float h = (height / density) - strokeThickness;
-			float x = strokeThickness / 2;
-			float y = strokeThickness / 2;
-			IShape clipShape = Clip.Shape;
+			float w = (width / density) - (isRoundRectangle ? (strokeThickness * 2) : strokeThickness);
+			float h = (height / density) - (isRoundRectangle ? (strokeThickness * 2) : strokeThickness);
+			float x = isRoundRectangle ? strokeThickness : strokeThickness / 2;
+			float y = isRoundRectangle ? strokeThickness : strokeThickness / 2;
 
 			var bounds = new Graphics.RectF(x, y, w, h);